The invention belongs to the technical field of lithium carbonate preparation, and discloses a method for preparing low-magnetism high-purity lithium carbonate by using saline lithium salt. The method using the saline lithium salt as a raw material mainly comprises the following steps: pulping the saline lithium salt, carrying out countercurrent washing, hydrogenating carbonic acid, removing magnetic substances, carrying out resin purification to remove impurities, carrying out evaporative crystallization, refining, calcining, and crushing to prepare the low-magnetism high-purity lithium carbonate product. The purity of the lithium carbonate product prepared through the method is 99.95-99.98%, and the contents of magnetic Fe, magnetic Cr and magnetic Zn in the product are not greater than 0.081g/t, not greater than 0.002g/t and not greater than 0.002g/t respectively. The method has the advantages of simplicity, stable operation process, short production period and small device investment, the prepared lithium carbonate is highly pure, contains a small amount of magnetic substances, has a comprehensive recovery rate of lithium of 98.65%, has a low production cost, and is suitable for industrial production.